Saturday, November 24, 2007

Responding to our Climate Emergency

Now I'm beginning to understand why there is panic just under the surface when climate scientists explain what's happening to our planet.

For years they have been trying to get through to us. They've used the careful, measured language of science, couching their worries in the uncertainty that is intrinsic in a system as complex as the global climate. NASA climate scientist Jim Hansen refers to this as the problem of "scientific reticence."

Some special interests (particularly those funded by the oil and coal industries) have taken advantage of this reticence, suggesting it means the greenhouse phenomenon, and the human causes, remain in doubt. The reality is that scientists continue to refine and test their models, but if anything, the behavior of the climate is following the worst-case scenarios.

Some changes associated with the climate happen in a gradual, linear way. More carbon leads to more warming, which expands the volume of the oceans, for example, and gradually raises sea levels. But Hansen is among those who shows that the effects of greenhouse gases on climate can have an abrupt, non-linear quality. When a little bit of warming melts the reflective ice covering the Arctic Ocean, the dark sea beneath absorbs heat. A warming ocean hastens the melting of ice, and you have a positive feedback loop in which the warming climate is fueling still more warming.

Likewise, when rising temperatures cause permafrost to melt, methane is released into the atmosphere -- a gas more than 20 times more powerful in its greenhouse effect than carbon. More methane, more warming, more melting permafrost, still more warming.

A third example of this run-away effect is the drying of the Amazon, which, when healthy, is an extraordinary recycler of moisture and a carbon sink (that is, it absorbs and safely stores carbon). As the Amazon dries, it burns, dies, and becomes a source of carbon. There are other examples of this dynamic.

Fortunately, there are also some negative feedback loops -- more warming should result in more cloud cover, for example, which can deflect the warming effects of the sun. But so far, the feedback loops that cause further warming appear to have the upper hand.

We appear to be very near a tipping point, after which the effects of global heating feed on themselves, and it may be that by the end of the century, the Earth will be, as Jim Hansen puts it, a very different planet.

Our editorial team is pouring over studies and reports as we work on the spring issue of YES! on climate change. We will be forthright about what the science is telling us. We don't plan to try to spin the story for the benefit of the oil and coal industry--or to avoid alarming people.

We are skirting very close to danger, and what we do in the next few years (Hansen says less than 10 years) may determine whether we get caught up in run-away effects that will mean a new climate equilibrium of gases and temperature on Earth that may or may not support human life.

Most agree that we can still avert the worst. But the needed changes really are "inconvenient" as Al Gore says. Business as usual -- new coal plants, more cars, exploiting the tar sands, the continuation and spreading of the "American dream" -- any of these could be disastrous for many species of life, including our own. And some of the responses could also set us on a destructive path that does more to benefit narrow private interests than to solve the climate problem—so-called "clean" coal plants, most bio-fuels, nuclear power.

On the other hand, the changes we make that rise to this global emergency could also have spin-off benefits, including providing millions of jobs, restoring community, reducing poverty, giving us a fresh start on building the infrastructure of our societies. And especially heartening, people worldwide are ready to "step up" to the challenge.

The spring issue of YES! will lay out a path to averting disaster and restoring the health of our planet home, while we still have time. Here's a preview: what we in the wealthy part of the world -- especially the U.S. -- decide to do will make the difference—and the tools, will power, and intelligence are already with us. More on that soon.

Labels: , ,

0 Comments:

Post a Comment

<< Home